Development and Validation of an Inductively Coupled Plasma – Atomic Emission Spectrometry (ICP-AES) Method for Trace Element Determination in Vinegar

Abstract

This study presents the determination of toxic and nutrient elements in vinegar samples using inductively coupled plasma – atomic emission spectrometry (ICP-AES). The determined elements were Pb, Ni, Cr, Cu, Mg, Zn, Fe, Al, Ba, Ca, Co, and Cd. The aim of this study was to develop a simple and rapid method for the elemental analysis of vinegar samples without sample dilution that can result in sensitivity loss and without acidic digestion that could significantly increase the time and complexity of the overall process. Therefore, direct analysis of vinegars was employed and parameters including the radiofrequency power and the sample uptake were evaluated, in order to have stable plasma conditions. Under the optimum conditions, vinegar samples with a maximum concentration of 6% v/v were analyzed using a radiofrequency power of 1350 W and a sample uptake of 1.5 L min−1. The proposed method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision. The LODs were between 0.1 and 22.1 μg L−1, while the LOQs were between 0.3 and 73.0 μg L−1 for the examined trace elements. The developed method was successfully employed for the analysis of 10 different commercially available vinegar samples that included white grape vinegar, red wine vinegar, apple cider vinegar, and balsamic vinegar.